The noise source of the motor can be divided into electromagnetic noise, machine noise and ventilation noise according to the cause of occurrence.
The magnetic field in the air gap of the motor is contaminated with each other and produces radial forces that change over time and space, which causes the stator core and frame to periodically deform over time, that is, the stator vibrates; electromagnetic noise is mainly caused by the vibration of the stator causing the surrounding atmosphere to pulsate. Load noise.
Centrifugal force caused by the rotor machine's unbalanced machine vibration and noise, bearing vibration and noise, brush and slip ring or commutator sliding friction noise, end cover axial vibration noise caused by bearing vibration, etc.
Atmospheric vortex noise caused by the rotation of electric fans or other ventilation elements and rotors, single-frequency noise caused by periodic pulsation of the cooling atmosphere or gas hitting obstacles due to the rotation of electric fans, resonance of thin-walled parts in the wind path, or unfair design of the wind path. Flute".